Over the Mountains and Beyond the Sea
by turtlegirl42
Summary: When Sans investigates an inter-dimensional anomaly, he soon discovers a cast of characters who could change the land of Undertale forever. Post True Pacifist ending with OCs.
1. Chapter 1

It had been a half a year since the human had saved the monsters of the Underground. Once aboveground, with Frisk as the ambassador of the monsters, they had adjusted very well. As it had turned out, they had been underground for so long that a good majority of humans outside of the mountain were unaware that they had even existed—monsters had simply became myth and legend rather than fact. So the human population's reaction to their appearance was more of shock than fear. And yeah, there was a fair share of prejudices among the humans, but that was to be expected. But no one was being killed—and that was more than Sans had expected.

At any rate, it had been, by all accounts, an average day. Frisk and Toriel had just left from a visit to Sans and Papryus's house. Papryus was now busy doing all the dishes from the spaghetti dinner he had made them, and Sans was at the kitchen table, doing a crossword puzzle.

"SO BROTHER, WHAT DID YOU THINK OF FRISK? THEY SEEMED TO BE DOING WELL. MORE IMPORTANTLY, WHAT DID YOU THINK OF MY SPAGHETTI?!"

Silence.

"BROTHER?"

Papryus turned around. Sans was no longer doing his crossword. Instead, he was staring straight ahead, and his eye sockets were empty. The permanent grin was still there, but Papryus knew he wasn't smiling.

"BROTHER, ARE YOU ALRIGHT?! WHAT IS GOING ON?!"

Sans blinked slowly. "hey bro."

"WHAT JUST HAPPENED?! I DEMAND AN ANSWER! ARE YOU OKAY?!"

"uhhh yeah i'm fine bro. i'm just... just really tired all of a sudden. i think i'm gonna go take a nap or something."

Papyrus jumped up and down in frustration. "I KNOW THAT'S NOT IT! THERE'S SOMETHING YOU'RE NOT TELLING ME! I DEMAND TO KNOW!"

"hey i'm sorry bro, maybe i'll tell you later. i'm not sure what's going on right now." Ignoring Papryus's further protests, he shuffled into his room and shut the door. And locked it.

Truth was, he had just _felt_ something. A shift. A shift... an anomaly in the timeline. Not a lot shocked Sans—after all, his knowledge far surpassed Papryus's or even Alphys's. But this...

He hadn't felt anything like this since Frisk had walked out of the Ruins.

And furthermore, there was something... different about this. After making sure the door was locked, Sans checked his machine, the one that detected shifts like this. The one that he and Gaster had built, years ago.

Sans's intuition had been right—there was a change detected by the machine. But it wasn't anything he had seen before. Perhaps it could be an interdimensional type shift, as the machine didn't detect any timeline distortions (as it had when Frisk had arrived). At this discovery, Sans breathed a sigh of relief. He didn't need to relive _that_ again.

But this whole thing was puzzling and intriguing. He considered presenting Alphyus with this development, but for the time being, decided to keep it to himself.

All he knew was, something was coming. And he had to be prepared for it.


	2. Chapter 2

Aheem sighed as he sat at his writing desk, the candle lighting his parchment. He picked up a quill, dipped it in an inkwell, and began to write a letter.

 _Dear Victor,_

 _I hope that you and Maxim are finding success in your efforts to obtain more information on the ancient Shadow Mage tradition. It has been some time since we have heard from you here, so we assume that you are busy but well._

 _Unfortunately, the plague is spreading quickly in this region. Victor, you must come back to Shorlin as quickly as possible. Celia has caught the plague and keeps asking for you in her feverish state._

 _Maxim, I may need your help. As slim as a chance this is, if you find ANY strange symbols like the ones I've copied down here in the library, please let me know. I have had an odd vision and I have a feeling that something important is trying to be conveyed._

He paused, taking a piece of parchment out of his robes covered in symbols. He painstakingly etched the symbols onto the letter. He put the parchment away and continued writing.

 _Travis sends his greetings as well. I believe he is getting lonely around here, but hopefully things change soon. At least one thing for the better, at least._

 _If I receive no reply, I will assume you are returning right away, and wish you the best of luck on your trip._

 _Sincerely, Aheem_

Aheem rolled up the parchment, tied it with a piece of twine, and approached a raven sitting on a perch in the corner of the room. He tied it to the bird's foot, and whispered, "Take this to the Forgotten Library on the Hielo Cliffs. It it urgent."

As the bird flew out the window, the dark-skinned mage sat back down at his desk and placed his head in his hands. Perhaps there would be hope in the future, but Aheem felt his determination slowly draining away...

Victor rolled up the parchment, tears in his eyes. He walked over to Maxim's bedroll and shook him. "Hey, are you sleeping? It's really important..." He was devastated by the news of his lover sick and possibly dying—he needed to leave immediately. But he needed permission from Maxim. Though of course Victor was willing to abandon his research, perhaps Maxim would want more time to wrap up any research before returning to Shorlin.

Maxim sat up and shook his head. "What is it?"

Victor looked very grave. He handed Maxim the parchment and the torchlight he had read it by. "Read this."

Maxim rubbed the sleep out of his eyes and read the letter from Aheem. "Oh no," he said quietly. He then almost dropped the torchlight. The symbols, he recognized them...

"Be careful!" Victor said, alarmed at Maxim's apparent clumsiness.

"No Victor – it's the symbols. I've seen them before. In the library. You must be very upset about Celia, but I need to go to the archives before we leave in the morning. I'll try to be as quick as possible. Aheem wouldn't joke about a vision or something like this."

* * *

When Victor and Maxim arrived, Victor immediately asked to see Celia.

"Do not touch her," Aheem said. "That is how we think the plague has been spreading."

After promising not to, he left, and Aheem and Maxim were left standing in the room. Maxim took out a sheet of parchment. "I found a codex to the symbols. The librarians were rather adamant that I not take the codex back, but I translated for you." He spread out the sheet on Aheem's desk.

 _There is hope over the mountains and beyond the sea._

Aheem frowned. "What is this supposed to mean?"

Maxim shrugged. "Victor was rather distressed on our trip home, so I had a lot of time to think about this. There must be somewhere we can get the cure for this plague. And it must be out in the Ardean Sea beyond the archipelago."

"That's really preposterous," Aheem said, with only a slight tone of disbelief.

"Well, we haven't gotten much to lose. No one has found a cure for this plague, no one knows where it has come from, and even though it's been traveling slowly, it may reach the capital eventually." Maxim took off his top hat and frowned. "I know Celia is not going to make it, but we'll need Victor's help."

"What about me?"

A tall skeleton with red, glowing eyes entered the room. Maxim turned to him and said, "Well, I thought you might want to wait for Jelar."

"I got a note from Jelar the other day. He's still on the run but safe. Said he wouldn't be back for a while though. Complicated stuff." The skeleton folded his arms. "I don't have anything to lose, either, you know. Can't catch the plague because technically, I'm already dead."

Aheem nodded. "This is true, Travis. We could use your help. Crossing the Ardean Sea may be a dangerous journey."

"Yeah, and finally I won't have to wear a stupid cloak in public." Travis was a talking skeleton, but he fell under the category of undead. He had been re-animated after death and somehow managed to retain personality, but no rememberence of a past life.

Aheem raised an eyebrow. "Finding the cure to a deadly plague might just be a little more important than you being able to go out in public."

Travis clattered his jaw noisely, because he knew it annoyed Aheem. "Well, it'll be a bonus then. I'll be up with Victor." He left the room.

Maxim rolled up the translated message. "I'll be back later. Have to make some preparations and research." He too left.

Aheem sighed and thought of the vision. He had had no other visions or dreams since, but the visage constantly haunted him. A being in black and white, with broken eyes and an almost sad smile. Who was this creature? And where was it going to lead them?


End file.
